text: /*
    Copyright (C) 2003-2015 Paul Brossier <piem@aubio.org>
  
    This file is part of aubio.
  
    aubio is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
  
    aubio is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
  
    You should have received a copy of the GNU General Public License
    along with aubio.  If not, see <http://www.gnu.org/licenses/>.
  
  */
  
  #ifndef AUBIO_FILTER_C_DESIGN_H
  #define AUBIO_FILTER_C_DESIGN_H
  
  /** \file
  
    C-weighting filter coefficients
  
    This file creates a C-weighting digital filter, which reduces low and high
    frequencies and enhance the middle ones to reflect the ability of the human
    hearing.
  
    The implementation is based on the following standard:
  
      - IEC/CD 1672: Electroacoustics-Sound Level Meters, IEC, Geneva, Nov.  1996,
    for A- and C-weighting filters.
  
    See also:
  
      - <a href="http://en.wikipedia.org/wiki/A-weighting">A-Weighting on
    Wikipedia</a>
      - <a href="http://en.wikipedia.org/wiki/Weighting_filter">Weighting filter on
    Wikipedia</a>
      - <a href="http://www.mathworks.com/matlabcentral/fileexchange/69">Christophe
    Couvreur's 'octave' toolbox</a>
  
    The coefficients in this file have been computed using Christophe Couvreur's
    scripts in octave 3.0 (debian package 1:3.0.5-6+b2 with octave-signal
    1.0.9-1+b1 on i386), with <pre> [b, a] = cdsign(1/Fs) </pre> for various
    sampling frequencies (8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000,
    88200, 96000, and 192000 Hz).
  
    The sampling frequency should normally be higher than 20kHz, but most common
    file sampling rates have been included for completeness.
  
    \example temporal/test-c_weighting.c
  
  */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /** create new C-design filter
  
    \param samplerate sampling frequency of the signal to filter. Should be one of
    8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and
    192000 Hz
  
    \return a new filter object
  
  */
  aubio_filter_t *new_aubio_filter_c_weighting(uint_t samplerate);
  
  /** set feedback and feedforward coefficients of a C-weighting filter
  
    \param f filter object to get coefficients from
    \param samplerate sampling frequency of the signal to filter. Should be one of
    8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and
    192000 Hz
  
  */
  uint_t aubio_filter_set_c_weighting(aubio_filter_t *f, uint_t samplerate);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* AUBIO_FILTER_C_DESIGN_H */
  